diff options
| -rw-r--r-- | arch/arm/Kconfig.debug | 12 | ||||
| -rw-r--r-- | arch/arm/include/asm/pgtable-2level.h | 1 | ||||
| -rw-r--r-- | arch/arm/include/asm/pgtable-3level.h | 1 | ||||
| -rw-r--r-- | arch/arm/mm/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/mm/dump.c | 345 |
5 files changed, 360 insertions, 0 deletions
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index 5765abf5ce84..0603a6a53902 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -2,6 +2,18 @@ menu "Kernel hacking" source "lib/Kconfig.debug" +config ARM_PTDUMP + bool "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + select DEBUG_FS + ---help--- + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + If in doubt, say "N" + config STRICT_DEVMEM bool "Filter access to /dev/mem" depends on MMU diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h index 86a659a19526..dfff709fda3c 100644 --- a/arch/arm/include/asm/pgtable-2level.h +++ b/arch/arm/include/asm/pgtable-2level.h @@ -160,6 +160,7 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr) return (pmd_t *)pud; } +#define pmd_large(pmd) (pmd_val(pmd) & 2) #define pmd_bad(pmd) (pmd_val(pmd) & 2) #define copy_pmd(pmdpd,pmdps) \ diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 4f9503908dca..03243f7eeddf 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -142,6 +142,7 @@ PMD_TYPE_TABLE) #define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \ PMD_TYPE_SECT) +#define pmd_large(pmd) pmd_sect(pmd) #define pud_clear(pudp) \ do { \ diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile index ecfe6e53f6e0..7f39ce2f841f 100644 --- a/arch/arm/mm/Makefile +++ b/arch/arm/mm/Makefile @@ -12,6 +12,7 @@ ifneq ($(CONFIG_MMU),y) obj-y += nommu.o endif +obj-$(CONFIG_ARM_PTDUMP) += dump.o obj-$(CONFIG_MODULES) += proc-syms.o obj-$(CONFIG_ALIGNMENT_TRAP) += alignment.o diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c new file mode 100644 index 000000000000..2b3a56414271 --- /dev/null +++ b/arch/arm/mm/dump.c @@ -0,0 +1,345 @@ +/* + * Debug helper to dump the current kernel pagetables of the system + * so that we can see what the various memory ranges are set to. + * + * Derived from x86 implementation: + * (C) Copyright 2008 Intel Corporation + * + * Author: Arjan van de Ven <arjan@linux.intel.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#include <linux/debugfs.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/seq_file.h> + +#include <asm/fixmap.h> +#include <asm/pgtable.h> + +struct addr_marker { + unsigned long start_address; + const char *name; +}; + +static struct addr_marker address_markers[] = { + { MODULES_VADDR, "Modules" }, + { PAGE_OFFSET, "Kernel Mapping" }, + { 0, "vmalloc() Area" }, + { VMALLOC_END, "vmalloc() End" }, + { FIXADDR_START, "Fixmap Area" }, + { CONFIG_VECTORS_BASE, "Vectors" }, + { CONFIG_VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" }, + { -1, NULL }, +}; + +struct pg_state { + struct seq_file *seq; + const struct addr_marker *marker; + unsigned long start_address; + unsigned level; + u64 current_prot; +}; + +struct prot_bits { + u64 mask; + u64 val; + const char *set; + const char *clear; +}; + +static const struct prot_bits pte_bits[] = { + { + .mask = L_PTE_USER, + .val = L_PTE_USER, + .set = "USR", + .clear = " ", + }, { + .mask = L_PTE_RDONLY, + .val = L_PTE_RDONLY, + .set = "ro", + .clear = "RW", + }, { + .mask = L_PTE_XN, + .val = L_PTE_XN, + .set = "NX", + .clear = "x ", + }, { + .mask = L_PTE_SHARED, + .val = L_PTE_SHARED, + .set = "SHD", + .clear = " ", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_UNCACHED, + .set = "SO/UNCACHED", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_BUFFERABLE, + .set = "MEM/BUFFERABLE/WC", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_WRITETHROUGH, + .set = "MEM/CACHED/WT", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_WRITEBACK, + .set = "MEM/CACHED/WBRA", +#ifndef CONFIG_ARM_LPAE + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_MINICACHE, + .set = "MEM/MINICACHE", +#endif + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_WRITEALLOC, + .set = "MEM/CACHED/WBWA", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_DEV_SHARED, + .set = "DEV/SHARED", +#ifndef CONFIG_ARM_LPAE + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_DEV_NONSHARED, + .set = "DEV/NONSHARED", +#endif + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_DEV_WC, + .set = "DEV/WC", + }, { + .mask = L_PTE_MT_MASK, + .val = L_PTE_MT_DEV_CACHED, + .set = "DEV/CACHED", + }, +}; + +static const struct prot_bits section_bits[] = { +#ifndef CONFIG_ARM_LPAE + /* These are approximate */ + { + .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE, + .val = 0, + .set = " ro", + }, { + .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE, + .val = PMD_SECT_AP_WRITE, + .set = " RW", + }, { + .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE, + .val = PMD_SECT_AP_READ, + .set = "USR ro", + }, { + .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE, + .val = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE, + .set = "USR RW", +#else + { + .mask = PMD_SECT_USER, + .val = PMD_SECT_USER, + .set = "USR", + }, { + .mask = PMD_SECT_RDONLY, + .val = PMD_SECT_RDONLY, + .set = "ro", + .clear = "RW", +#endif + }, { + .mask = PMD_SECT_XN, + .val = PMD_SECT_XN, + .set = "NX", + .clear = "x ", + }, { + .mask = PMD_SECT_S, + .val = PMD_SECT_S, + .set = "SHD", + .clear = " ", + }, +}; + +struct pg_level { + const struct prot_bits *bits; + size_t num; + u64 mask; +}; + +static struct pg_level pg_level[] = { + { + }, { /* pgd */ + }, { /* pud */ + }, { /* pmd */ + .bits = section_bits, + .num = ARRAY_SIZE(section_bits), + }, { /* pte */ + .bits = pte_bits, + .num = ARRAY_SIZE(pte_bits), + }, +}; + +static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t num) +{ + unsigned i; + + for (i = 0; i < num; i++, bits++) { + const char *s; + + if ((st->current_prot & bits->mask) == bits->val) + s = bits->set; + else + s = bits->clear; + + if (s) + seq_printf(st->seq, " %s", s); + } +} + +static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u64 val) +{ + static const char units[] = "KMGTPE"; + u64 prot = val & pg_level[level].mask; + + if (addr < USER_PGTABLES_CEILING) + return; + + if (!st->level) { + st->level = level; + st->current_prot = prot; + seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + } else if (prot != st->current_prot || level != st->level || + addr >= st->marker[1].start_address) { + const char *unit = units; + unsigned long delta; + + if (st->current_prot) { + seq_printf(st->seq, "0x%08lx-0x%08lx ", + st->start_address, addr); + + delta = (addr - st->start_address) >> 10; + while (!(delta & 1023) && unit[1]) { + delta >>= 10; + unit++; + } + seq_printf(st->seq, "%9lu%c", delta, *unit); + if (pg_level[st->level].bits) + dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num); + seq_printf(st->seq, "\n"); + } + + if (addr >= st->marker[1].start_address) { + st->marker++; + seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + } + st->start_address = addr; + st->current_prot = prot; + st->level = level; + } +} + +static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start) +{ + pte_t *pte = pte_offset_kernel(pmd, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PTE; i++, pte++) { + addr = start + i * PAGE_SIZE; + note_page(st, addr, 4, pte_val(*pte)); + } +} + +static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start) +{ + pmd_t *pmd = pmd_offset(pud, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PMD; i++, pmd++) { + addr = start + i * PMD_SIZE; + if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd)) + note_page(st, addr, 3, pmd_val(*pmd)); + else + walk_pte(st, pmd, addr); + } +} + +static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) +{ + pud_t *pud = pud_offset(pgd, 0); + unsigned long addr; + unsigned i; + + for (i = 0; i < PTRS_PER_PUD; i++, pud++) { + addr = start + i * PUD_SIZE; + if (!pud_none(*pud)) { + walk_pmd(st, pud, addr); + } else { + note_page(st, addr, 2, pud_val(*pud)); + } + } +} + +static void walk_pgd(struct seq_file *m) +{ + pgd_t *pgd = swapper_pg_dir; + struct pg_state st; + unsigned long addr; + unsigned i, pgdoff = USER_PGTABLES_CEILING / PGDIR_SIZE; + + memset(&st, 0, sizeof(st)); + st.seq = m; + st.marker = address_markers; + + pgd += pgdoff; + + for (i = pgdoff; i < PTRS_PER_PGD; i++, pgd++) { + addr = i * PGDIR_SIZE; + if (!pgd_none(*pgd)) { + walk_pud(&st, pgd, addr); + } else { + note_page(&st, addr, 1, pgd_val(*pgd)); + } + } + + note_page(&st, 0, 0, 0); +} + +static int ptdump_show(struct seq_file *m, void *v) +{ + walk_pgd(m); + return 0; +} + +static int ptdump_open(struct inode *inode, struct file *file) +{ + return single_open(file, ptdump_show, NULL); +} + +static const struct file_operations ptdump_fops = { + .open = ptdump_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int ptdump_init(void) +{ + struct dentry *pe; + unsigned i, j; + + for (i = 0; i < ARRAY_SIZE(pg_level); i++) + if (pg_level[i].bits) + for (j = 0; j < pg_level[i].num; j++) + pg_level[i].mask |= pg_level[i].bits[j].mask; + + address_markers[2].start_address = VMALLOC_START; + + pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, + &ptdump_fops); + return pe ? 0 : -ENOMEM; +} +__initcall(ptdump_init); |
